Flat botart pump



p 1954 F. c. BYRAM ETAL FLAT ROTARY PUMP Original Filed April 29. 1950 m y im m Q ifo z v INEN TORS. C! Bram now 6. L. (Ha/v6,

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AITO RNEYS.

Reissued Sept. 21, 1954 FLAT ROTARY PUMP Frederick Cameron Byram, S. L. Chang, Bobbins it: My

and Sheldon l ors to enw ca ug om, ew or as- Inc., Springfield,

bin. a corporation of Ohio Original No. 2,590,751, dated March April 29, 1950. tion 10, 1953, Serial No. 380,85}

(Cl. l03-l33) [I appears-in the original patent but forms no part oi this italics indicates the additions made by reissue.

rial No. 159.078, for reissue June 8 Claims.

Hatter enclosed in he"! brackets rshsue specification; matter printed in This invention relates to a [flat] rotary pump oi entirely novel design. It relates more particularly to a rotary pump wherein one 01' the pumping elements may be fixed and the other subjected to a compound movement wherein there are a minimum of moving parts.

It is an object oi the present invention to provide such a novel pump which will be relatively simple to manuiacture and thereiore less expensive than comparable pumps now available. It is another object oi our invention to provide a pump such nature that there is no need for the individual pumping elements to be matched to each other whereby production may be greatly speeded up.

It is yet another object oi the present invention to provide a device as above outlined which. with relatively minor modification, may be made in the form 01' a pump, a compressor or an expander without departing irom the principles 01' this invention.

These and other objects of our invention which will become apparent as the specification proceeds or which will be pointed out in more detail hereinafter we accomplish by that certain construction and arrangement oi parts oi which we shall now describe one exemplary embodiment. Reference is made to. the drawings forming a part hereoi and in which:

Figure 1 is a central cross sectional view through a pump according to the present invention.

Figurezisa elements.

Figure 3 is a cross on the line 3-3 of Figure 2 Figure 4 is a plan view or the other pumping element, and

Figure 5 is a cross sectional view 01' the other pumping element taken on the line 5-8 01' Figure 4.

Briefly, in the practice of our invention we provide a pump having two pumping elements, one oi which may be tired and the other oi which is subjected to a compound movement with respect to the first. The pumping elements [are] may be. generally speaking. iiat and have on their mutually opposed iaces generally spiral threads. In the particular embodiment disclosed the fixed element or stator has a double thread, while the movable element or rotor has a single thread. It will oi course be understood that the positions oi the two elements could be reversed so that the single thread element could be the stator and the double thread element could be the rotor.

plan view oi one oi the pumping sectional view of the same elements. They Applies or opposite directions and still produce a pumping action.

It the rotor and stator are superimposed on each other, it will be found that the pumping pockets are arcuate in shape and pointed at both ends. Since the circumierence oi a circle increases in direct proportion to the radius, it will be clear that ii the pitch oi the s iral threads oi rotor and stator are constant tne volume oi the pumping pockets will not be the same as the pocket moves across the interiace oi the pumping will be smaller near the center the periphery. Thus, ii the are provided with threads of and larger near device will be an expander. Ii, conversely, the rotor is rotated in a direction to cause the pockets to move inwardly, the device they pass irom the center toward the periphery or vice versa. in other words, the threads must be closer together at the periphery than they are at the center. Under these conditions there will be provided constant volume pumping pockets and the device will operate as a constant volume pump no matter in which direction the rotor is rotated with respect to the stator.

Rei'erring now more specifically to Figure 2. the pumping element there shown is. in the particular embodiment illustrated-the rotor, and is the numeral II. The numeral Ii crest oi the thread which iollows from the center outward.

indicated by indicates the a p ral 98th ment has two indicated respectively at It and II. Figures 3 and 5 respectively show cross sectional views oi the rotor and stator oi Figures 2 and 4 respectively.

The assembly oi the pump is shown in Figure 1. The pump is provided with a head indicated at shown and may be provided with threads is tor the attachment oi pipe thereto. course has the central hole is ior it and aplate If or which integral casting is bolted The casing member is which may be as shown from a ring may of course be an to the head II as at II. provided with a port opening ll threaded as shown.

Cast integrally with the plate I! or welded thereto as shown is provided a sleeve ll. The sleeve 24 may be provided with ball bearings I for the drive shaft II and preferably suitable sealing means will be provided as indicated generally at 21. The particular sealing means form no part oi the present invention and will therefore not be described in de Power may be applied to the shaft 26 by means of a suitable elecin any desired as pointed out above. This motion involves a rotation of the rotor about an axis which is tilted with respect to the stator axis and the axis of tilt of the rotor moves azimuthally, or nutates. with respect to the stator. The movement of the rotor axis is analogous to the movement of the axis of a spinning top except that the axis of tilt remains constant.

In order to provide for the movement above outlined a universal Joint must,be provided. As shown in Figure i, there is secured to the rotor III by means of bolts 28 a cup 25 having an accurately bored hole therein at ill. The drive shaft 25 terminates in a portion ll of reduced diameter on th end of which is provided a spherical terminus II. The ball 8! fits accurately within the hole I6 and turning movement is transmitted from the shaft to the rotor by means of a pin 33 fitting tightly in diametrically opposed holes in the cup 29 and passing through a slot 34 which at its center is of a size to snugly fit th pin 38 but which flares at its end to permit of a rocking movement of the pin 33 with respect to the ball 32.

From the foregoing description it will be clear that as the shaft 26 rotates the pumping element Hi is caused to rotate also. But by virtue of the configuration of the threads II, I! and I6, the rotation of the element ll will be accompanied by a wobbling or nutating movement of the tilt axis in a direction opposite to the direction of rotation of the shaft 26.

The specific configurations of the surfaces of the rotor and stator members are fully disclosed and claimed in the copending application of Sheldon S. L. Chang, Serial No. 159,077, filed April 29, 1950 co-pending with the present case, now Patent No. 2,590,435, dated March 25, 1952. A machine for turning the pumping elements is disclosed and claimed in the co-pending application in the names of Chang and Hagerman Serial No. 146,344, filed February 25, 1950, now Patent No. 2,566,116, dated August 28, 1951. For a fuller understanding of the nature of the surfaces in volved and methods of production of such surfaces, reference is made to said copending applications.

In the embodiment illustrated it will be preferable that the port ll be the intake port and the port 24 be the exhaust port. Thus the fluid being pumped would be pressing the rotor against the stator so that a tighter fit would be produced whereby slip is reduced. It follows from what has been said that the precision ofthe components is not too critical. Thus, one of the two members may be made from molded rubber-like material and the other may probably be made as a die casting without further machine work. Itwillalsonotbenecessarytoemploy any selective fitting process because of the considerations mentioned above.

It will also be clear that the stator member may be made double sided or, in other words, it could consist in effect of two stator members back to back with a rotor operating against each surface. In this manner a double acting pump or multiple pump can easily be provided.

It will also be clear that the stator member itself may be a part of the casing head and does not need to be a separate member secured to the casing head. Similarly the pump casing may be made a part of the motor casing of the drive motor with simply a partition wall between the two and sealing means for the shaft.

Numerous other modifications will suggest themselves to those skilled in the art, and we therefore do not intend to limit ourselves otherwise than as set forth in the claims which follow.

Having now fully described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A pump comprising a pair of pumping elements, a universal joint, one of said elements having a single spiral thread and the other of said elements having a double spiral thread, said threads progressing outwardly from their respective axes, one of said elements being fixed, and the other having its axis at an angle to the axis of the first, and being rotationally driven through said universal joint, whereby said driven element will turn in one direction about said tilted axis, while said axis of tilt is nutating in the opposite direction, said pumping elements being enclosed within a casing having intake and exhaust ports.

2. A pump according to claim 1, wherein the pitch of said spiral threads constantly decreases with an increase in their distance from the center of said elements, whereby constant volume pumping pockets are provided.

3. A pump according to claim 1, wherein the pitch of said spiral threads is constant, whereby the volume of the pumping pockets decreases as the pockets move inward, whereby said pump operates as a compressor.

4. A pump according to claim 1, wherein the pitch of said spiral threads is constant, whereby the volume of the pumping pockets increases as the pockets move outward, whereby said pump operates as an expander.

5. A pump comprising a pair of pumping elements. one of said elements having a double spiral thread and being fixed, the other 01' said elements having a single spiral thread, said threads progressing outwardly from their respective axes, said other element being arranged for compound movement with respect to said fixed element, said arrangement comprising a drive shaft rotating on a fixed axis, and a universal joint connection between said drive shaft and said other element, said compound motion comprising a rotation of said element about a tilted axis, accompanied by a nutational movement of said axis of tilt, said pumping elements being enclosed within a casing having intake and exhaust ports.

6. A pump according to claim 5, wherein the pitch of said spiral threads constantly decreases with an increase in their distance from the center of said elements, whereby constant volume pumping pockets are provided.

'7. A pump according to claim 5, wherein the pitch of said spiral threads is constant, whereby the volume of the pumping pockets decreases as 5 fliepoeteilmoveinwermwherebynidpumaop- Number eaten a a 4 2. 1 17 I. A pump according to claim 5. wherein the 2,324,168 pitch 0! mid spin] thread: in constant. whereby 2,359,979

thevoiumeolthemmv lpocketlinereueeu 5 2,512,704 the pocket! mm mud. whereby eaidmmh opereeeeumexpender.

Name Date George Aug. 90. 1940 Monteiius July 13, 1949 Thompson July 11. 1944 Byram June 27, 1950 FOREIGN PATENTS Country Date Denmark Sept. 21, 1921 Austria July 11, 1932 Great Britain Feb. 18. 1992 Great Britain Jan. 21, 1936 Great Britain M 7 4, 1949 France Mar. 1. 1937 Certificate of Correction Reissue No. 23,870 September 21, 1954 Frederick Cameron Byram et :11.

It is hereby certified that error appears in the above numbered patent requiring correction as follows:

In the heading to the drawing, line 2; and in the headi to the printed specification, line 2, title of invention, for FLAT RO ARY PUMP read ROTARY PUMP and that the said Letters Patent should be read as corrected above.

Signed and sealed this 23rd day of November, A. D. 1954.

ARTHUR W. CROCKEB,

Assistant Oomnz'aaiomr of Patents. 

